MXPA97001548A - Rubber article that has a destruction design for high resistance to the abras - Google Patents

Abstract

The present invention relates to a rubber article having a surface construction designed for abrasion resistance, the surface area is characterized by a series of rubber layers parallel to each other and at a density of at least 200 layers per 25.4 millimeters as measured in a direction perpendicular to the layers along the surface area of the article

Description

"RUBBER ARTICLE THAT HAS A SURFACE DESIGN FOR HIGH RESISTANCE TO ABRASION" BACKGROUND OF THE INVENTION The present invention relates to a rubber article having a surface designed for high resistance to abrasion. Many products that are produced today are designed for high abrasion resistance. Examples of these products include running surfaces for pneumatic tires and shoe soles. Conventionally, the various components of these rubber articles are selectively combined to improve abrasion resistance. Examples include various rubbers and fillers or fillers. Even when there is an endless search to find components to improve the abrasion resistance of rubber articles, unexpectedly a new way has been found to improve the abrasion resistance of a surface of a rubber article, using conventional additives.

COMPENDIUM OF THE INVENTION The present invention relates to a rubber article having a surface construction designed for abrasion resistance, the surface comprising a series of rubber layers parallel to each other and at a density of at least 200 layers per inch. 25.4 millimeters as measured along the surface of the article and in a direction perpendicular to the layers.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates schematically a multi-layer article of the present invention. Figure 2 is a schematic illustration of a method for manufacturing a multi-layer article in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to Figure 1, the rubber article 1 of the present invention is characterized by at least one surface 2,4 which is designed for high abrasion resistance. Examples of rubber articles that are designed to have a surface area for high abrasion resistance include a surface of rolling of a tire, shoe soles, railroad crossings, contact pads with the floor of the tank, seals, belts and hoses. The surface area that is designed for high abrasion resistance comprises a series of layers of rubber 6, 8, 10 which are parallel to one another. The density of the layers 6, 8, 10 must be at least 200 layers per 25.4 millimeters as measured in a perpendicular direction (shown as an arrow) to the layers 6, 8, 10 along the surface area of the article. . Preferably, the density varies from about 200 to 21,000 layers per 25.4 millimeters. Most preferably, the density varies from about 5,000 to 15,000 layers per 25.4 millimeters. The rubber layers 6, 8, 10 may be of the same thickness or the thickness of the layers may be different. Generally speaking, each layer 6,8,10 has a thickness ranging from about .001 to about .15 millimeter, preferably, the thickness of each layer 6,8,10 ranges from about .0017 to about .005 millimeter. . The parallel rubber layers 6, 8, 10 can be oriented in a variety of directions along the surface of the article. For example, the parallel rubber layers can be oriented towards the surface area 2,4 of article 1, in a direction that is perpendicular to the flat where abrasion resistance is desired. According to another embodiment, the rubber layers can be oriented towards the surface area in a direction that is parallel to the plane in which abrasion resistance is desired (not shown). Depending on the degree of abrasion resistance, the layers 6, 8, 10 can be oriented parallel to different degrees with respect to the plane in which resistance to abrasion is expected. Each rubber layer 6, 8, 10 comprises of a rubber compound. Representative rubbers that can be used in the rubber compound include acrylonitrile / diene copolymers, natural rubber, halogenated butyl rubber, butyl rubber, cis-1, 4-polyisoprene, copolymers of styrene and butadiene, cis-1,4-polybutadiene, styrene-isoprene-butadiene terpolymers and mixtures thereof (please see provide any of the other rubbers that are currently proposed to be used). Preferably, the rubber is copolymers of acrylonitrile-diene and in particular, copolymers of acrylonitrile and butadiene. Each rubber layer may comprise the same rubber composition or alternative layers may be of a different rubber composition. The rubber compound preferably contains a filler or plate loading material. Representative examples of filling or loading materials in Plaques include talc, clay, mica and a mixture thereof. When used, the amount of the filler or plate charge varies from about 25 to 150 parts per 100 parts by weight of rubber (hereinafter referred to as phr). Preferably, the level of the filler or plate-loading material in the rubber compound ranges from about 30 to about 75 phr. The various rubber compositions can be stirred with conventional rubber mixing ingredients. Commonly used conventional ingredients include carbon black, tackifying resins, processing aids, anti-oxidants, anti-ozonants, stearic acid, activators, waxes, oils, sulfur vulcanizing agent and peptizing agents. As is known to those skilled in the art, depending on the desired degree of abrasion resistance, certain additives mentioned above are commonly used in conventional amounts. Typical additions of carbon black comprise from about 10 to 150 parts by weight of rubber, preferably from 50 to 100 phr. Typical amounts of tackifying resins comprise from about 2 to 10 phr. Typical amounts of processing aids comprise from 1 to 5 phr. Typical amounts of anti-oxidants comprise from 1 to 10 phr. The typical amounts of anti-ozonants comprise from 1 to 10 phr. Typical amounts of stearic acid comprise from 0.50 to about 3 phr. Typical amounts of waxes comprise from 1 to 5 phr. Typical amounts of oils comprise from 2 to 30 phr. Typical sulfur vulcanization agents include elemental sulfur, amine disulfide, polymeric polysulfides, sulfur olefin adducts and mixtures thereof which are used in an amount ranging from about 0.2 to 8 phr. Typical amounts of peptizers comprise about 0.1 phr. The presence of relative amounts of the aforementioned additives is not considered as being an aspect of the present invention. In accordance with a preferred embodiment, the co-driving curatives are separated into adjacent parallel layers. For example, when the layers are prepared, they are often heated to facilitate flow, heat can also be generated by mechanical working of the rubber. For rubbers that contain healing, the heat associated with this processing can induce healing or at least begin the process. To avoid these possibilities, it is preferred to separate the coercive curatives in adjacent parallel layers. For example, sulfur can be stirred in layer A and not include accelerators; however, layer B, which is parallel to A will contain accelerators but not sulfur. The A layer will follow. During the curing temperature, the sulfur and accelerators will migrate to adjacent layers and the article of the present invention becomes easily curable. Other curatives may also be separated such as zinc oxide, or zinc stearate in one layer and the sulfur and accelerator in the next layer. This will be appreciated after having read the present application, a person skilled in the art will appreciate the various methods by which the claimed rubber articles can be formed. For example, the different layers can be placed inside a mold in a manner so that the orientation of the layers is in accordance with the present invention. A critical aspect of the present invention is that the layers have the desired thickness. One method in which the desired thicknesses can be repaired is the use of a multiple layer of the extrusion apparatus to the matrix. The layers can be formed in a number of ways. For example, one method involves the use of two separate extrusion apparatuses that generally feed two but not necessarily different rubber compounds to a point of convergence where the two feeds come together to create a bi-layer. This bi-layer is then Feeds through a series of matrices, each of which doubles the number of layers in the extruded material. In this way, the original two-component layer (AB) is converted into four layers (ABAB) after the first matrix element and eight layers (ABABABAB) after passing through the second matrix element. Figure 2 illustrates the principle of layered arrays. Another method of co-extruding multi-layer laminates is described in U.S. Patent No. 3,557,165. Although extrusion apparatuses are a preferred means of preparing compounds with large numbers of very thin layers (e.g., more than 10,000 layers per 25.4 millimeters), other less elaborate means are also possible for preparing thin multiple layers. A calender can be used to prepare thin sheets of polymeric material which can subsequently be bent into alternate layers and possibly further thinned by the application of pressure. By repeated bending and thinning, compounds with several hundred layers per 2.54 centimeters can be easily prepared.

Example 1 Molded rubber blocks were prepared having a surface area of a series of rubber layers parallel to each other at a density of approximately 11,000 layers per 25.4 millimeters as measured in a direction perpendicular to the layers throughout the area superficial. The blocks were prepared in layers in accordance with the process shown in Figure 2. The multi-layer extrusion apparatus consisted of two separate high-temperature plastic extrusion apparatus, 19 millimeters (diameter) 24/1 L / D purchased from The Killion Co. , Cedar Grove, New Jersey. The extrusion apparatuses fed two compounds to a point of convergence where the feeds come together to create a bi-layer. The bi-layer was fed through a series of matrices that were obtained from DSM (Dutch School Mines / Techinal University) of Eindhoven, Holland. Each matrix doubles the number of layers in the extruded material. In this way, the two original layers are converted into four layers after passing through the first matrix element, and eight layers after passing through the second matrix element. Seven matrix elements were used to form 256 compounds in layers (11,000 layers by 25.4 millimeters). The first rubber article (Sample 1) in accordance with the present invention, had layers alternatives of two different rubber compounds. The first rubber compound contained 43 parts by weight of polybutadiene, 4 parts by weight of natural rubber, 96.25 parts by weight of SBR diluted with oil (PLF 1712C), 95 parts by weight of carbon black and conventional amounts of stearic acid, waxes, processing oil, antidegradants, primary and secondary accelerators, zinc oxide and sulfur. The second rubber compound contained 100 parts by weight of NBR ((Chemigum® N300), 50 phr of talc and conventional amounts of antidegradants, stearic acid, zinc oxide, accelerators and sulfur. molded rubber not placed in layers (Sample 3) containing a 50/50 mixture of the aforementioned polybutadiene-containing compound and the NBR-containing compound In addition, a non-layered molded rubber block (Sample 4) containing only the polybutadiene rubber compound and a non-layered molded rubber block (Sample 5) containing only the NBR compound The Din abrasion tests (both at room temperature and hot) according to the Test Method of the American Society for Testing Materials ISO 4649-1895 (E), were carried out on the samples. Sample 1 was tested when the abrasion was in the direction against the edges of the layers. Sample 2 (Control) was tested when the abrasion was flat to the surface; that is, only one layer covered the entire side of the sample when the abrasion was tested. Sample 3 (Control) was the non-layered mixture of the two rubber compounds. Sample 4 (Control) was the non-layered polybutadiene natural rubber, the SBR rubber compound. Sample 5 (Control) was the non-layered NBR rubber compound. Table 1, which is presented below, lists the respective DIN abrasion values for samples 1 to 5.

TABLE I Control Control Sample 1 Sample 2 Sample 3 Abrasion of hot Din 97 937 286 Abrasion of DIN at room temperature 84 940 316 TABLE I (CONTINUED) Control Control Sample 4 Sample 5 Abrasion of hot Din 174 135 Abrasion of DIN at room temperature 160 125 Since these tests measure the loss in weight, the lower the values the better the abrasion resistance, as can be seen, the abrasion values varied drastically with orientations of the layers.

Claims (11)

R E I V I N D I C A C I O N E S:

1. A rubber article having a surface construction designed for abrasion resistance, the surface area is characterized by a series of rubber layers parallel to each other and at a density of at least 200 layers per 25.4 millimeters as measured in a direction perpendicular to the layers along the surface area of the article.

2. The rubber article according to claim 1, characterized in that the density varies from about 200 to about 20,000 by 25.4 millimeters.

3. The rubber article according to claim 1, characterized in that the alternative layers along the surface area comprise a different rubber composition than the interdispersed layers therein.

4. The rubber article according to claim 1, characterized in that the alternative layers along the surface area comprise the same rubber composition.

5. The rubber article according to claim 1, characterized in that the rubber layer It is of the same thickness that is measured in the perpendicular direction.

6. The rubber article according to claim 1, characterized in that the alternative layers along the surface area are of a different thickness as measured in the perpendicular direction. The rubber article according to claim 1, characterized in that each layer has a thickness ranging from about .001 to about .15 mm. The rubber article according to claim 1, characterized in that the rubber layers are oriented towards the surface area of the article, in a direction that is perpendicular to the plane to which the abrasion resistance is designed. 9. The rubber article according to claim 1, characterized in that the article is in the form of a rolling surface of a rim, shoe soles, railroad crossings, contact pads with the floor of the tank, seals, a strap or a hose. 10. The rubber article according to claim 9, characterized in that the rubber compocontains from about 25 to 150 phr of a filler material in plates that is selected from the group consisting of talc, clay, mica and mixtures thereof. The rubber article according to claim 3, characterized in that the alternative layers containing sulfur and non-accelerators and the interdispersed layers therein contained accelerators and not sulfur.